Sidney f



S. F. SHELBOURNE.

SUBMARINE TELEGRAPH GABLE.

(No Model.)

. Patented Apr. 22, 1884.

N. PETERS. Pholo-Lilhagrapher. Washington. D. c.

arena was.

SIDNEY F. SHELBOURNE, OF NEV YORK, N. Y.

SUBMARlNE-TELEGRAPH CABLE.

$PECIFICATION forming part of Letters Patent No. 297,180, dated April22, 1884.

Application filed September 8, 1883. (No model.)

.Zo aZZ whom it may concern:

Be it known that I, SIDNEY F. SHELBOURNT, a citizen of the UnitedStates, residing in the city of New York and State of New York, haveinvented a new and useful Telegraph Cable for Submarine and alsoUnderground Communication; and I do hereby declare that the following isa full and clear description of my invention.

The chief difficulty in operating long submarine or subterraneanelectric cables is by reason of what is known as static charge, due to agreatly-increased capacity of the conduct or in such a situation toreceive and store up the electric energy of the battery within thecable, and its insulation, so that a notable interval passes before theelectric force has arrived at the remote end of the cable to give itssignal, and hence this delay in giving the proper signal has beenassigned to a retardation of the current by reason of the phenomena just mentioned. The Atlantic cables are now worked through the medium ofa condenser, which is, in fact, but a modification of the Leydenjarcoatings, and involving the same philosophical principles. \Vhile someadvantages are secured by this arrangement, the chief features of thedifficulty still remain. It is a well-known fact that if the outercoating of the Leyden jar is insulated from the earth no charge, exceptas indicated by one or two feeble sparks, can be given to its interiorcoating. Professor Henry, who patiently investigated the laws of dynamicinduction as developed in insulated bands of copper and coils of finewire in proximity to each other, showed conclusively that an interposingcoil between two others did not prevent induction between them as longas its two ends were not connected together; but did effectually do soon joining the two ends with each other. It has been shown thatelectricity, whatever the agency of its production, is one in itsnature, and static charge and dynamic induction, at least when attendinga battery-current, are identical in cause and correlated in theprinciples or laws which govern them. The philosophical theory uponwhich induction proceeds, assuming two fluids, is that a positivecurrent repels through an insulation its like and attracts its opposite.If, then, the outer coating of the Leyden jar is connected with theearth-aninfinite reservoirandtheinterior of the jar supplied with thepositive element, the like element leaves the outer coating for theearth,and an inexhaustible supply of the neg ative element is readytomount to the outer coating in proportion as the positive element issupplied to the interior coating. This same theory would properlyaccount, in dynamic eleotricity,for the induced currents in oppositedirections to the inducing ones in adjacent insulated conductors whereboth have their circuits completed, either metallic or through theearth; but if the circuit is not completed, either in the one way or theother, in the adjacent Wire,no current andno dynamic induction can ensuein that conductor. It becomes inert, and neither shows a currentitselfnor prevents one, nor does it prevent static charge by influencesthrough or from beyond it. Experimenters in England found,therefore,that an outer metallic coating over the insulation of the conductingcable wire gave no relief from the difficulties of static charge, itbeing a fact that this coating was in communication with the earth alongits Whole length, and therefore, so far as induction is concerned, itmay be taken as being a part of the earth. Even had it been insulatedlaterally and connected to earth at its ends, so far as static chargealone is considered, the earths vast source of negative element couldsupply the conditions of static charge along the wire from either end,and especially the end next to the battery giving the positive current.From what has j ust been said, there- .fore, the object and scope of thepresent inven tion will readily be understood. It is to provide aboutthe conducting wire or core of a cable a completed and insulatedmetallic circuit not connected with the earth, but completelysurrounding the conductingcore and inter posed between it and the earth.This will be best illustrated by reference to the drawings making partof this specification, in which Figure 1 is an enlarged cross-section ofthe cable. Fig. 2 is a longitudinal perspective of the several layers ofthe cable from the conducting-core outward; and Fig. 3 is a similar Viewof a portion of cable, showing at its end, by a full and also by adot-ted curved line, the connections between the three metallicconducting-channels within the insulation of the cable.

In Fig. 2, a represents what is usually called the conducting-core ofthe cable, and composed of several small wires wound together. This coreis covered with a thin insulation, 1), preferably wound fiber saturatedwith the hi ghest quality of insulating material. There follow upon 1)four narrow copper strips, 0 c c 0, about one-eighth of an inch wide andone sixtieth to one hundredth of an inch in thickness. These are woundby twos in opposite and very long spirals about 1). Another thininsi'ilation, d, quite similar to b, is then applied over the strips 0 cc c. There follows over the insulation (I a thin copper covering e,whoseconductivity will be about one-hal 1' greater than that of c c c c andabout or nearly equal to that of the core a. Over 6 is applied the usualnumber of insulating-coatings, f m a,whieh are o-t'te11 varied in theuse of di l'terent compounds for each. There is shown also in thedrawings the usual protecting-shield, of heavy iron or steel wires.surrounding the coatings of insulation.

In Fig. 3, w shows a connection between caud the strips 0 c c 0, while ashows an alternative connection between cand a, in which case thecombined strips 0 c c c are used-as conductors for the signal-currents.The alternative connections are made identical at both ends of thecable. As to the operation of the arranged conductors, it will besecnthat it' a carries the signal-current it will act inductively on c cc c, inducing a current in an opposite direction to its own; but it willalso act by direct induction on 0 through the spaces between the strips0 c c c. As a is greater than the combination of a both in conductivityand surface, the current in c, passing to the ends of the cable, whereit is connected with c c c a, will overbalance that in c, andconsequently produce a current in c of negative quality in the samedirection with the positive (we will assume to be) in a at the batteryend As only the negative electricity naturally in c and e is availableby first induction to the positive attraction of a, and not'theintinitefund of the whole earth, it will be seen that the current in a cannot bestored beyond its equality with the negative in c and c. XVhen, on theother hand, the alternative connection is made-2 (3., that of a withc-and the combination of c is used as the signal-coiuluctor, it will beseen that the current'in a will actinductively both ways, inwardly on aand outwardly on c, tending to cause a current in each opposite to itsown direction. Now, since a and c are taken to be of eqn a1conducti\-ity,and are insulated laterally, but joined together at bothends of the cable, these currents will evidently be in oppositedirections in the same round circuit, and therefore exactlybalance eachother; but the react-- ive induction strain of both of them on thesignal-current in 0 will be in the same direction with it. 4

It will be seen that to produce the result reached in the secondarrangement it is not necessary that the conductor 0 should be composedof strips, but may entirely envelop the insulation of a, in likemanneras d completely surrounds them both. I therefore do not conline myinvention to the employment of c in the open arrangement, as shown.

\Vhat is claimed as new is- A submzn'ine and subterranezim electriccable composed of three conductors insulated from each other, onecentral and the others annular about it, combined so that the central orfirst annular forms the sigcal-conductor, and the ends of the remainingtwo are connected toget her, completing an imluction-guard circuit, asherein set forth.

SIDNEY F. SHELBOURNF.

\Vitnesses:

FRANK S. TYLER, T. L. KENNEDY.

